1. Field of the Invention
The present invention relates to a throttle controller for controlling a throttle (valve) in a vehicle comprising an automatic transmission.
This application is based on Patent Application No. Hei 9-353788 filed in Japan, the contents of which are incorporated herein by reference.
2. Description of the Related Art
Generally, in conventional vehicles comprising an automatic transmission having a hydraulic torque converter, when the throttle (valve) thereof is opened in accordance with the amount of force exerted on the accelerator (pedal) while the gear lever is in a driving gear (or setting), the driving force of the engine is transmitted via the transmission system including the torque converter, clutch, and the like, to the wheels. Japanese Patent Application, First Publication, No. Hei 7-332479 discloses an example of such an automatic transmission, which comprises a lock-up clutch controller. In addition to the driving setting for activating the automatic transmission (operation), recently-developed automatic transmissions may include a holding gear (or setting) for holding the gear ratio specifically fixed.
When the gear lever is in a driving gear, the target driving force is calculated by a target driving force calculating means, based on the degree of depression of the accelerator. In order to drive the engine based on the calculated value, a throttle control section determines a target degree of opening of the throttle so as to control the throttle. In contrast, in the holding gear, the throttle is controlled in one-to-one (or unique) correspondence to the degree of depression of the accelerator.
Therefore, the degree of opening of the throttle with respect to the degree of depression of the accelerator is not consistent between the driving gear and the holding gear; thus, the driving efficiency is degraded when the gear lever is changed from the driving setting to the holding setting, or when changed from the holding setting to the driving setting.
On the other hand, recently-developed automatic transmissions may comprise a manual gear (or setting) in which a one-step down or up-shift operation can be performed by moving forward or back the gear lever. Also in this case, it is required to improve the driving efficiency when the gear lever is changed from the driving setting to the holding setting, or when changed from the holding setting to the driving setting.